Heat exchange unit



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HEAT EXCHANGE UNIT Filed June 14, 1968 .Z J iVENTOR Char/es TBapp/erymagw ATTORNEY United States Patent 3,519,070 HEAT EXCHANGE UNIT CharlesT. Bappler, Menlo Park, Edison, N.J., assignor to Coolenheat, Inc.,Linden, N.J., a corporation of New Jersey Filed June 14, 1968, Ser. No.746,720 Int. Cl. F28f l /36 U.S. Cl. 165-184 2 Claims ABSTRACT OF THEDISCLOSURE The present invention relates to a heat exchange unitcomprising a tube for carrying fluid therethrough with a helical finstrip wrapped therearound with the inner edge or circumference of thethin strip being provided with undulations so as to contact the outersurface of the tube upon which it is disposed over its entire length toprovide a maximum path of heat transfer into or out of the fin strip.The unit further is provided with its helical circumferential portiondisposed away from the tube provided with a plurality of means to spreadthe distribution of the fluid carried in the tube to adjacent surfacesor other tubes having fin strips thereon.

The present invention relates to a heat exchanger unit and moreparticularly to a unit in which a fluid is passed through a tube andanother fluid is passed around the exterior of the tube so that a heatexchange transfer takes place. The tubes may have a cooler fluid passedtherethrough, such as a gas or a liquid, and another gas may be passedin heat exchange relationship around the exterior of the tube so thatthe gas flowing around the outside of the tubes is cool. On the otherhand, the heat transfer may be in reverse wherein the hot gas or a hotliquid flows through the interior of the tube and the gas or air beingpassed around the exterior of the tubes is heated thereby.

In such an arrangement, in order to increase the efliciency of the heattransfer from the fluid passing through the tube and the air or thefluid passing around the exterior of the tube, the tube, or the entireheat exchanger, which generally comprises a plurality of rows of tubes,is provided with extended surface area. The extended surface area maycomprise a form of helical fin or continuous strip of material that canbe wound around the tube.

It is an object of the present invention to provide a heat exchange unitin which the tubing is provided with an extended surface wrappedtherearound and in contact with the outer surface of the tube so as toprovide a maximum amount of contact area between the tube and the finprovides a maximum path of heat transfer into or out of the fin.

It is an object of the present invention to further provide a continuousstrip of fin that is wrapped around a heat transfer tube having an innercircumferential portion comprising a continuous zig-zag edge in contactwith the outer surface of the tube to form a path of heat transfer intoor out of the fin.

It is yet another object of the present invention to provide a helicalfin tube in which the inner surface of the fin tube is crimped ordeformed to provide a serrated configuration that is in contact alongits entire edge with the outer surface of the tube.

It is yet another object of the present invention to provide a helicalfin for a tube in which the outer circumferential portion of the helicalfin is provided with means for dividing or separating the outercircumferential portion into a plurality of segments or individualportions so that the individual segments can spread the distribution ofthe fluid across the outer edge of the fin and so carry 3,519,070Patented July 7, 1970 the fluid more evenly to the next adjacent row offinned tubes directly adjacent the first tube or first row of tubes.

It is yet another object of the present invention to provide a helicalfin strip for winding around a tube in which the outer circumferentialportion of the fin is in segmented form that permits the fin strip to beeasily wound around the tube.

It is yet another object of the present invention to provide a helicalfinned tube in which a helical continuous fin strip having crimpedalternating undulations adjacent the inner circumferential portionthereof provide a maximum path of heat transfer from the tube to the finand which tube is further provided with means adjacent the outercircumferential portion of the fin strip for a more uniform and widerdistribution of the fluid across the bottom edge of the fin strip so asto carry the fluid more evenly down to a row of fin tubes disposeddirectly below a first row of fin tubes.

It is yet another object of the present invention to provide a fin tubewith a continuous helical fin wrapped therearound and having a crimpedinner circumferential portion so as to supply more total surface withthe same number of fins per inch and more fin edge in contact with thetube for better total heat transfer which will permit, for example, theuse of four rows of finned tubes per unit, instead of the conventionalrequirement of six rows per unit.

It is still another object of the present invention to provide a novelfin tube which has a more exposed surface totally per lineal foot, alldimensions of tube and fin and fin spacing being equal, and morecross-sectional area of fin in contact with the tube for greater heattransfer.

It is yet another object of the present invention to provide a fin tubehaving an extended surface thereon which provides approximately fortypercent more total exposed surface per lineal foot of finned tube,without the disadvantage of having less spread-out distribution of thefluids from one row to the row below, as in a conventional crimped fin.

Varius other objects and advantages of the present invention will bereadily apparent from the following detailed description when consideredin connection with the accompanying drawing forming a part thereof andin which:

FIG. 1 is a perspective view illustrating the fin tube embodied in thepresent invention;

FIG. 2. is a cross-section taken along the lines 22 of FIG. 1;

FIG. 3 is an enlarged section taken along the lines 33 of FIG. 2;

FIG. 4 is a view illustrating the distribution of fluids fro mone row tothe row below when utilizing the finned configuration of the presentinvention; and

FIG. 5 illustrates the fluid distribution of a conventional fin tube nothaving the configuration of the present invention.

Referring to the drawing, the reference numeral 10 generally designatesa tubular member or tube through which is passed a fluid such as liquidor gas so as to cause a heat transfer or heat exchange relationship tooccur between the fiuid passing through the tube and fluid passingaround the exterior of the tube. The tubes are generally disposed inrows and spaced one above the other so as to form a heat exchange unit.

Each tube is provided with a winding or continuous coil of extendedsurface material generally designated 12 there around. The extendedsurface material comprises a helical winding so as to form a helical finor strip consisting of a series of individual turns 14 spaced closelyadjacent each other to provide a heat transfer surface. The innerperiphery or circumference of the turns are 3 crimped together so as toform a series of undulations or alternate substantially U-shapedconfigurations 18, as best seen in FIG. 3. The helical fin 12 hasgenerally parallel outer and inner edges and 22, respectively. The innercircumferential portion of the helical fin strip is pressed against theouter surface of the tube so that the entire edge of the continuousstrip is in contact with the tube. Thus, the cross-sectional area of thefin edge 22 in contact with the tube is the thickness of the fin timesthe outside circumference of the fin, not the tube, and the path of heattransfer into or out of the fin is substantially more than with aplurality of individual extended surface fins disposed on a tube.

It will be noted that the helical fin consists of a flat or coplanarmiddle and outer circumferential portions 24 the latter having aplurality of individual spaced apart sections 26. These sections orsegments 26, as illustrated in the drawing, are provided by V-shapedslots 28 made in the outer portion of the fin strip.

If desired, a bonding material may :be applied between the inner edge 22of the fin strip and the outer surface of the tube surface, by any wellknown means, so that there is substantially one hundred percent contactbetween the edge of the helical fin strip and the surface of the tube,should there be any high or low spots in the outer surface of the tubeor the inner edge of the helical strip. If desired, the V-shaped slots28 can be substantially radially cut so as to divide the outercircumferential portion 24 of the fin strip into spaced individualsections in order have a spread-out distribution of the fluids from onerow to a next adjacent row of finned tubes.

Referring to FIG. 4, it will be seen that there are a series of dottedlines indicating the advantage of the individual plurality of segmentsor sections adjacent the outer circumferential portion of the continuoushelical fin strip with the dotted lines illustrating the spread-outdistribution of the fluids from one row to the row below Referring toFIG. 5, the dotted rows of lines therein indicate the convergingdistribution of the fluids from one row to another row of fin tubeswhere the spaced or individual outer circumferential sections are notprovided in a finned tube.

Thus, from the foregoing description, it is apparent that the finnedtube configuration or construction of the present invention provides ahelically wound fin strip of extended surface area around a tube for usein a heat exchanger or heat transfer relationship in which the innercircumferential portion of the helical strip is provided with aplurality of undulations that are disposed to have substantiallycomplete contact with the outer surface of a tube so as to provide amaximum path of heat transfer into or out of the fin, while the outercircumferential portion of the helically wound fin strip is providedwith means therein dividing the outer circumferential portion into aplurality of individual sections so as to provide a maximum spread-outdistribution of the fluids from one fin tube or row of fin tubes toanother row of fin tubes below it.

Inasmuch as various changes may be made in the form, location andrelative arrangement of the several parts without departing from theessential characteristics of the invention, and it is to be understoodthat this invention is not to be limited, except by the scope of theappended claims.

What is claimed is:

l. A heat transfer unit comprising a tubular member having a continuousextended surface member helically wound thereon, said extended surfacemember comprising parallel outer and inner circumferential portions anda middle portion, said inner circumferential portion having its entireinner edge formed of alternate U-shaped crimped undulations, bondingmaterial disposed on said inner circumferential portion and the outersurface of said tubular member to provide substantially one hundredpercent contact between said surfaces to compensate for high and lowspots in said tubular member, said middle portion extendingsubstantially perpendicular to said tubular member and its entire areabeing disposed in the same plane, said outer circumferential portionbeing coplanar with said middle portion and having circumferentiallyspaced cutout portion in its outer edge dividing it into individualsegments to provide spread out distribution of fluid heat transfer fromone tubular member to another.

2. The unit of claim 1 wherein said slots are of V-shape.

References Cited UNITED STATES PATENTS 1,689,568 10/1928 Wade 29-157.3

2,117,445 5/ 1938 Niemchek -184 2,529,545 11/1950 Edwards 165184 FOREIGNPATENTS 1,006,374 9/1965 Great Britain.

ROBERT A. OLEARY, Primary Examiner T. W. STREULE, Assistant Examiner US.Cl. X.R. 2 9-157.3

